(define (script-fu-rs-resize filename new-width new-height)
  (let* ((image    (car (gimp-file-load RUN-NONINTERACTIVE filename filename)))
         (drawable (car (gimp-image-active-drawable image)))
        )

     (gimp-image-scale image new-width new-height)
     (gimp-file-save   RUN-NONINTERACTIVE image drawable filename filename)
  )
)